Epoxidation of Z -ethyl cinnamate

The (Z)-ethyl cinnamate was obtained by hydrogenation of ethyl phenyl propiolate using Lindlar s catalyst (5% palladium on calcium carbonate, poisoned with lead) in w-hexane under an atmospheric pressure of hydrogen. The mixture, containing 75% of the (Z)-ethyl cinnamate, 22% of the overreduced alkane and 3 % of the (E )-ethyl cinnamate, was used without further purification. 666 mg of this mixture contains 500 mg of (Z)-ethyl cinnamate (2.55 mmol). 

A solution was prepared by mixing an aqueous solution of sodium hydro-genphosphate (0.05 M, 10 mL) and a solution prepared with concentrated bleach (sodium hypochlorite, 5mL) in water (20 mL). The pH of the resulting solution was adjusted to 11.25 by addition of few drops of hydrogen chloride 1 M or sodium hydroxide 1M. 

A 100 mL flask, was filled with (Z)-ethyl cinnamate, (666 mg of the mixture containing 75 % of (Z)-ethyl cinnamate), 4-phenylpyridine N-oxide (116 mg) and dichloromethane (6mL). Jacobsen s catalyst (108 mg) was then added. 

The resulting organic solution and the buffered bleach (16 mL) were cooled separately using an ice-bath and then combined at 4 °C in the flask. 

After 5 minutes the cooling bath was removed and the two-phase reaction mixture was stirred at room temperature. The reaction was monitored by TLC (eluent petroleum ether-diethyl ether, 9 1). (Z)-Ethyl cinnamate was UV active, Rf 0.42. The epoxide visualized withp-anisaldehyde dip stained yellow, Rt 0.28. 

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